The proposed study is a continuation and expansion of the previously funded project that will further investigate substance use among male and female Mexican American school-age students. The specific aims for the proposed project follow from the original proposal and are expanded to describe the focus of the current proposal. The specific aims of the research are a) to document changes in the prevalence and patterns of substance use as the baseline sample (the original sample from the preceding proposal and a new group of subjects) of Mexican American students move into high school. Gender differences will be emphasized; b) to examine the effects of school transition (from middle school to high school) on risk factors and their association with self reported substance use among Mexican American students; c) to examine the impact of family factors as they relate to substance use in a Mexican American school-age population; d) to more thoroughly examine the issue of acculturation as it relates to the use of substances and the variables related to substance use among Mexican American-school age children; e) to further assess and examine risk factors that were found to be associated with self-reported substance use among Mexican American students in the preceding proposal; f) to develop a comprehensive predictive model of substance use among male and female Mexican American students using the longitudinal data collected over a 3 to 7 year period (this includes data from the preceding and the present proposals). The data will be collected over the first 4 consecutive years of the five year proposal. Seventh, 8th and 9th grade students (estimated baseline N=3,000) along with their randomly selected parents and teachers will be tracked as they advance through middle school into high school. With the inclusion of familial and acculturation variables in the present proposal, multivariate statistical procedures will be used to further explore and assess the predictive risk factors associated with substance use. Because the data is to be collected through three sources and over four time points, structural equation modeling techniques will be conducted to examine the causal relations between the risk factors (either antecedents or mediators) and the use of substances in Mexican American youth.